Accession Number : ADP008044

Title :   Substrate Effects on X-Ray Specular Reflectance and Non-Specular Scattering from X-Ray Multilayers,

Corporate Author : CALIFORNIA UNIV BERKELEY LAWRENCE BERKELEY LAB

Personal Author(s) : Kortright, J.B. ; Nguyen, T.D. ; Tidswell, I.M. ; Lucas, C.A.

Report Date : 05 MAR 1992

Pagination or Media Count : 3

Abstract : It is common knowledge that substrate roughness plays an important role in limiting the specular reflectance of x-ray multilayers. However, there have been relatively few systematic experimental studies of the effects of substrate roughness on x-ray multilayer reflectivity. We have begun to investigate these effects by measuring the specular and off-specular scattering from a set of substrates with different roughness and from tungsten/carbon multilayers deposited simultaneously onto an identical set of substrates. The substrates were polished fused-silica and were flat to better than lambda/10 (lambda visible) at low spatial frequencies. The higher spatial frequency microroughness was varied during the polishing process, and was quantified by the optical polisher using a ZYGO Model 5500 Heterodyne Profiler at visible wavelengths to yield an rms roughness (sigma visible) and a peak-to-valley roughness (PV). Substrates with four distinct microroughness levels were studied. The sigma visible values for these substrates were roughly 0.2, 2.0, 5.0 and 10.0 angstroms, and the corresponding PV values were 1.4, 12, 32 and 65 angstroms, respectively. Tungsten/carbon multilayers were deposited by magnetron sputtering to have 40 periods each 30 angstroms thick in which the tungsten layers comprised roughly 0.4 of each period.

Descriptors :   *LAYERS, *REFLECTANCE, *ROUGHNESS, *SCATTERING, *SUBSTRATES, *X RAYS, *SPECULAR REFLECTION, CARBON, FREQUENCY, FUSED SILICA, INTENSITY, MAGNETRONS, MEASUREMENT, MODELS, POLISHING, RADIATION, REFLECTIVITY, SPUTTERING, SURFACES, SYNCHROTRONS, TUNGSTEN, VALLEYS, VALUE, YIELD, OPTICAL EQUIPMENT, OPTICS.

Subject Categories : Laminates and Composite Materials
      Optics
      Electricity and Magnetism
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE